An X-ray radiography device obtains a radiograph by radiating a predetermined amount of X-rays, which are generated by an X-ray generator, to a predetermined portion of a body to be radiographed, sensing the amount of X-ray passing through the portion by means of an X-ray sensing unit, and calculating X-ray absorption ratios of predetermined points in the portion of the body. In the X-ray radiography device, the X-ray generator needs be easily changed in position and direction to face desired portions of a subject and the position and direction need to be fixed while an X-ray is generated after they are determined.
FIG. 1 shows an X-ray radiography device having a plurality of arms in the related art. The X-ray radiography device 10 of the related art, as shown in FIG. 1, includes a body 11 that is fixed to a wall or other equipment and an X-ray generator 12 that radiates an X-ray to a subject, in which they are connected through an arm assembly 20 having a plurality of joints. A power supply and a control panel are disposed at the body 11, while an X-ray emitter and a collimator are disposed at the X-ray generator 12. An X-ray sensing unit (not shown) may be provided inside or outside a subject that the X-ray generator 12 faces.
The arm assembly 20 is formed by connecting a plurality of unit arms 21, 22, 23, and 24. Adjacent unit arms 21, 22, 23, and 24 are connected by various joints so that they can rotate about rotational shafts a1˜a7, respectively, within the range of 0 to 180 degrees. The unit arms 21, 22, 23, and 24 and the joints function as paths for a power supply line and signal lines connecting the body 11 and the X-ray generator 12.
In order to perform radiography using the X-ray radiography device 10, for example, for dental examination and treatment, a user puts the X-ray sensing unit, which is called an intraoral X-ray sensor, inside the mouth of a patient and has to operate the arm assembly 20 so that the X-ray generator 12 faces the X-ray sensing unit. In particular, patients have different sizes, so the user has to appropriately configure the X-ray generator every time toward the desired portions to radiograph of the patient. However, it is difficult to control the position and direction of the X-ray generator 12 by operating the arm assembly 20. This is because it is required to consider the lengths of the unit arms 21, 22, 23, and 24 of the arm assembly 20 and the rotational characteristics of the joints should avoid interference with the body of a patient. Further, considering the weight of only the X-ray generator 12 is around 10 kg, it is hard for a user to move the arm assembly 20 supporting the arm.
Further, in terms of manufacturing the device, the structure is complicated due to the plurality of unit arms and joints, and the manufacturing cost and the percent defective are easily increased and the reliability is easily deteriorated in proportion to the number of the parts.